Zylkene and Feliway are your friends here. Zylkene is a milk protein that binds to the same receptor as diazepam having the anti-anxiety effects without the addictive ones. It works best started 7 days before the stressful event and continue 7 days after. Feliway a pheromone product in a plug in diffuser or spray form ideally both. On move day spray box 15mins before cat gets in, then arrival at new house spray 'cats room' 15 mins before putting cat in room and also plug in diffuser at same time. Feliway and zylkene seem to work synergistically. Finally do not disinfect the litter tray on moving day empty out old litter and then put fresh in so it retains your cat's smell.
I would defiantly limit her range to one quiet room, slowly allowing her access to more of the house as you get more settled. Cats love boxes so let her sleep in one as the high sides will make her feel safe. Put her scratching post with her as it will have her smell and try to be as quiet as possible round her. If possible put her in a room in your old house and move her strait into her new room in your new house. Don't scold her if she has an accident, unfortunately it is something that they do when thy are stressed. And feliway is your friend!